The influence of HLA phenotypes on the response to parenteral gold in rheumatoid arthritis.

One hundred and ten patients with rheumatoid arthritis (RA) were studied for a possible influence of HLA phenotypes on the reaction to parenteral gold in the first 6 months of treatment, in terms of both clinical response and toxicity. Frequencies of HLA-B8 and -DR3 were significantly increased in patients who responded excellently to gold treatment as compared with non-responders (p = 0.04 for both antigens). On the other hand, for HLA-DR7 there was a tendency for increased frequency in non-responders versus excellent and moderate responders (p less than 0.03; Pc = n.s.). Drug toxicity was higher in excellent than in non-responders (p less than 0.04), being exceptionally high in male excellent responders (85% versus 33% in females, p less than 0.01), probably due to the increased frequency in B8 and DR3 in the excellent responder group as a whole and in the excellent responder males in particular. We conclude that HLA antigens B8 and DR3 co-determine both toxicity and excellent clinical response to parenteral gold, whereas the presence of DR7 is possibly associated with non-response. In addition, we found sex differences in reaction to parenteral gold, which may be related to an increased frequency of HLA-B8 and -DR3 in male RA patients.